Syndiotactic styrene polymers

ABSTRACT

Styrene homo-or-co- polymers, the stereoregularity of which is mainly syndiotactic are disclosed, having repeating unit or two or more different repeating units defined by a general formula (I): ##STR1## wherein each R may be the same or different. And a method of preparation of syndiotactic copolymers wherein there are two different repeating units represented by formula (I); wherein the polymerization is carried out with a catalyst comprising (a) a titanium compound and (b) a contact product of a organoaluminum compound and a condensing agent such as water.

This is a continuation-in-part of U.S. patent application Ser. No.07/416,914 filed Oct. 4, 1989 which is a continuation-in-part of U.S.patent application Ser. No. 07/175,581 filed Mar. 28, 1988 (abandoned)which is a continuation of Ser. No. 06/888,153 filed Jul. 18, 1986(abandoned). Ser. No. 07/416,914 is also a continuation-in-part of Ser.No. 07/138,914 filed Dec. 28, 1987 (abandoned).

BACKGROUND OF THE INVENTION

The present invention relates to styrene polymers including homopolymersand copolymers having a new stereoregular structure and moreparticularly to styrene polymers in which the stereoregular structure ofsaid chains relative to the polymer main chain is mainly syndiotactic.

As is well known, styrene homopolymers such as polystyrene andpolyparamethylstyrene, and styrene copolymers are generally produced bytechnique such as radical polymerization, anionic polymerization,cationic polymerization and polymerization using Ziegler-type catalysts.These styrene polymers are divided into three groups, isotactic,syndiotactic and atactic polymers, depending on the steric configurationof side chains thereof. It has heretofore been known that usual radial,anionic and cationic polymerization methods provide styrene polymershaving mainly an atactic structure, and that the polymerization methodsusing Ziegler-type catalyst provide styrene polymers having mainly anisotactic structure.

SUMMARY OF THE INVENTION

The present invention is intended to provide styrene polymers having asyndiotacic structure. As a result of extensive investigations, it hasbeen found that polymerization of styrene monomes in the presence of acatalyst comprising specific transition metal compounds andorganometallic compounds results in styrene polymers of highsyndiotactic structure.

The present invention relates to a styrene polymer having a singlerepeating unit (homopolymer) or at least two different repeating units(copolymer) which can be represented by the formula (I): ##STR2##(wherein each R is individually selected from hydrogen atom, a halogenatom or a substituent containing a carbon atom, an oxygen atom, anitrogen atom, a sulfur atom, a phosphorus atom or a silicon atom, and nrepresents an integer of 1 to 3), having a degree of polymerization ofnot less than 5, and having a stereoregular structure which is mainlysyndiotactic.

The present invention further relates to a process for producing styrenecopolymers which comprises copolymerizing at least one styrene-basedmonomer represented by the general formula (A'): ##STR3## (wherein R'and m have definition selected from the definitions as R and nrespectively in the general formula (I) and different styrene-basedmonomer represented by the general formula (B')): ##STR4## (wherein R²and n are selected from the same definitions as R and n respectively inthe general formula (I)) (excluding the same as the styrene-basedmonomer or monomers of the general formula (A')) in the presence of acatalyst comprising (a) a titanium compound and (b) a reaction productof an organoaluminum compound, and water as a condensing agent.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows ¹³ C-NMR spectra (aromatic ring C₁ carbon signals) ofstyrene polymers produced in examples; (a) indicates polystyreneproduced in Example 1, (b) indicates, atactic polystyrene produced inComparative Example 1, (c) indicates isotactic polystyrene produced inComparative Example 2, (d) indicates poly (p-methylstyrene) produced inExample 23, (e) indicates poly (m-methylstyrene) produced in Example 24,(f) indicates poly (p-terbutylstyrene) produced in Example 25, (g)indicates poly (p-chlorostyrene) produced in Example 26, (h) indicatesatactic poly (p-chlorostyrene) produced commercially, (i) indicates poly(m-chlorostyrene) produced in Example 27, and (j) indicates poly(p-fluorostyrene) produced in Example 28;

FIG. 2 shows ¹³ C-NMR spectra (methine methylene carbon signals) ofstyrene polymers produced in example: (a) indicates polystyrene producedin Example 1, (b) indicates atactic polystyrene produced in ComparativeExample 1, (c) indicates isotactic polystyrene produced in ComparativeExample 2, and (d) indicates poly(p-methylstyrene) produced in Example23;

FIG. 3 shows ¹ H-NMR spectra of styrene polymers produced in examples:(a) indicates polystyrene produced in Example 1, (b) indicates isotacticpolystyrene produced in Comparative Example 2, and (c) indicates poly(p-methyl-styrene) produced in Example 23;

FIG. 4 shows X-ray diffraction patterns of styrene polymers produced inexamples: (a) indicates polystyrene produced in Example 1, (b) indicatesisotactic polystyrene produced in Comparative Example 2 and (c)indicates poly(p-methylstyrene) produced in Example 23; and

In FIG. 4, the symbol θ indicates a Bragg angle (°).

FIG. 5 shows infrared absorption spectra of styrene polymers produced inexamples: (a) indicates polystyrene produced in Example 1, (b) indicatesatactic polystyrene produced in Comparative Example 1, (c) indicatesisotactic polystyrene produced in Comparative Example 2, and (d)indicates poly (p-methystyrene) produced in Example 23.

FIGS. 1A(b), 4A(b), 5A(b), 9A(b), 11A(b), 12A(b) and 14A(b) representthe ¹ H-NMR spectra of the polymers or copolymers obtained in theexamples and comparative examples.

FIGS. 1A(a₁), 1A(a₂), 2A, 3A, 4A(a₁), 4A(a₂), 5A(a₁), 5A(a₂), 6A, 7A,8A, 9A(a), 10A, 11A(a), 12A(a), 13A, 14A, 15A, 16A, 17A, 18A, 19A, 20Aand 21A represent ¹³ C-NMR spectra of the styrene copolymers obtained inthe examples and comparative examples.

DETAILED DESCRIPTION OF THE INVENTION

The styrene polymers of the present invention have one or more differentstructure units (repeating unit) represented by the above generalformula (I) and include, as well as polystyrene, variousnucleus-substituted polystyrenes such as poly(alkyl-styrene),poly(halogenated styrene) and copolymers thereof.

Each R or R¹ or R² in the formulas herein, can be selected from amonghydrogen, a halogen such as chlorine, bromine and iodine, or asubstituent containing carbon, oxygen, nitrogen, sulfur, phosphorus, orsilicon.

Representative example of the carbon atom-containing substituent are analkyl group having 1 to 20 carbon atoms (e.g., a methyl group, an ethylgroup, an isopropyl group and a tert-butyl group), and ahalogen-substituted alkyl group having 1 to 20 carbon atoms (e.g., achloromethyl group, a bromomethyl group and a chloroethyl group).

Representative examples of the carbon atom and oxygen atom-containingsubstituents are an alkoxy group having 1 to 10 carbom atoms (e.g., amethoxy group, an ethoxy group and an isopropoxy group), and acarboxyester having 1 to 10 carbon atoms (e.g., a carboxymethylestergroup and a carboxyethylester group).

Representative examples of the carbon atom and silicon atom-containingsubstituent are an alkylsilyl group (e.g., a trimethylsilyl group).

Representative examples of the carbon atom and nitrogen atom-containingsubstituent are an alkylamino group having 1 to 20 carbon atoms (e.g., adimethylamino group), and a cyano group.

Representative examples of the sulfur atom-containing substituent are asulfonyl group, a sulfonic acid alkyl ester group, an alkylthio groupand a mercapto group.

Representative example of the phosphorus atom-containing substituent aea phosphoric acid ester group, a phosphorus acid ester group and analkylphosphinyl group.

Representative examples of the styrene polymers of the present inventionare polystyrene; poly(alkylstyrene) such as poly(p-methylstyrene),poly(m-methylstyrene), poly(o-methylstyrene), poly(2,4-dimethylstyrene),poly(2,5-dimethylstyrene), poly(3,4-dimethylstyrene),poly(3,5-dimethylstyrene) and poly(p-tert-butylstyrene);poly(halogenated styrene) such as poly(p-chlorostyrene),poly(m-chlorostyrene), poly(o-chlorostyrene), poly(p-bromostyrene),poly(m-bromo-styrene), poly(o-bromostyrene), poly(p-fluorostyrene),poly(m-fluorostyrene), poly(o-fluorostyrene) andpoly(o-methyl-p-fluorostyrene); poly(halogen-substituted alkyl-styrene)such as poly (p-chloromethylstyrene), poly(m-chloromethylstyrene) andpoly(o-chloromethylstyrene); poly-(alkoxystyrene) such aspoly(p-methoxystyrene), poly(m-methoxystyrene), poly(o-methoxystyrene)poly(p-ethoxystyrene), poly(m-ethoxystyrene) and poly(o-ethoxystyrene);poly(carboxy-esterstyrene) such as poly(p-carboxymethylstyrene),poly(m-carboxymethylstyrene) and poly(o-carboxymethylstyrene);poly(alkyletherstyrene) such as poly(p-vinylbenzylpropyl-ether);poly(alkylsilylstyrene) such as poly(p-trimethyl-silylstyrene);poly(ethyl vinylbenzenesulfonate); andpoly-(vinylbenzyldimethoxyphosphide); and copolymers thereof.

When the styrene polymer of the present invention is a copolymer of twoor more different monomers then the different repeating unitsrepresented by formula (I) can be represented as (A) and (B), below.That is, the styrene polymers of the present invention relate to styrenecopolymers which comprise at least one structural unit represented bythe general formula (A): ##STR5## (wherein R¹ (as defined above) can bea hydrogen atom, a halogen atom, or a carbon, oxygen, nitrogen, sulfur,phosphorus or silicon-containing group, m is 1, 2 or 3, and when m is 2or 3, R's may be the same or different) and a structural unitrepresented by the general formula (B): ##STR6## (wherein R² (as definedabove) can be a hydrogen atom, a halogen atom, or a carbon, oxygen,nitrogen, sulfur, phosphorus or silicon-containing group, n is 1, 2 or3, and when n is 2 or 3, R² s may be the same or different) (excludingthe same as the structural unit;

Representative example of resulting copolymer units are shown below.

Alkylstyrene units such as a styrene unit, a p-methylstyrene unit, am-methylstyrene unit, an o-methylstyrene unit, a 2,4-dimethylstyreneunit, a 2,5-dimethylstyrene unit, a 3,4-dimethylstyrene unit, a3,5-dimethylstyrene unit and a p-tert-butylstyrene unit; halogenatedstyrene units such as a p-chlorostyrene unit, a m-chlorostyrene unit, ano-chlorostyrene unit, a p-bromostyrene unit, a m-bromostyrene unit, ano-bromostyrene unit, a p-fluorostyrene unit, a m-fluorostyrene unit, ano-fluorostyrene unit and an o-methyl-p-fluorostyrene unit;halogen-substituted alkylstyrene units such as a p-chloromethylstyrenegroup, a m-chloromethylstyrene unit and an o-chloromethylstyrene unitlalkoxystyrene units such as a p-methoxystyrene unit, a m-methoxystyrene,an o-methoxystyrene unit, a p-ethoxystyrene unit, a m-ethoxystyrene unitand an o-ethoxystyrene unit; carboxyesterstyrene units such asp-carboxymethylstyrene unit, a m-carboxymethylstyrene unit and ano-carboxymethylstyrene unit; alkyletherstyrene units such as ap-vinylbenzylpropyl ether unit; alkylsilylstyrene units such as ap-trimethylsilystyrene unit; ethyl vinylbenzenesulfonate unit, andvinylstyrene units such as a vinylbenzyldimethoxy phosphide unit and ap-vinylstyrene unit.

STEREOREGULARITY

The stereoregular structure of the styrene polymers of the presentinvention is mainly syndiotactic; that is, the styrene polymers of thepresent invention have such a steric configuration that phenyl groups orsubstituted phenyl groups as side chains are positioned alternately onthe opposite sides in relation to the main chain comprisingcarbon-carbon bond. The tacticity of the styrene polymers is determinedby the nuclear magnetic resonance (NMR) method.

More specifically, the tacticity of the styrene polymers is determinedby analyzing the signal of C₁ carbon of an aromatic ring and the signalof methine.methylene carbon in ¹³ NMR (nuclear magnetic resonancespectrum as measured using an isometric carbon), or the proton signal of¹ H-NMR.

The tacticity can be determined by NMR for each given number ofconstituting units connected continuously, such as a diad in which thenumber of constituting units is two, a triad in which the number ofconstituting units is three, and a pentad in which the number ofconstituting units is five. The term "polymer having mainly asyndiotactic structure" as used herein means that the polymer has such asyndiotactic structure that the syndiotacticity expressed in terms ofthe diad is not less than 85%, or the syndiotacticity expressed in termsof the pentad is not less than 30% and preferably not less than 50%.

However, the degree of syndiotacticity which has been obtained variessomewhat depending on the presence and type of the substituent orsubstituents in the structural units (I) (or (A) and (B)). Thus, styrenepolymers not always satisfying the above-defined value ranges butwherein the degree of syndiotacity is increased over conventionalstyrene polymers are also included in the present invention. Thus,styrene polymers having mainly a syndiotactic structure of the presentinvention include the following polymers; polystyrene in which thesyndiotacticity expressed in terms of the diad is not less than 75%, orthe syndiotacticity expressed in terms of the pentad is not less than30%;

Poly(p-methylstyrene) in which the syndiotacticity expressed in terms ofthe diad is not less than 75%, or the syndiotacticity expressed in termsof the pentad is not less than 30%;

poly(m-methylstyrene) in which the syndiotacticity expressed in terms ofthe diad is not less than 75%, or the syndiotacticity expressed in termsof the pentad is not less than 35%;

poly(o-methylstyrene) in which the syndiotacticity expressed in terms ofthe diad is not less than 85%, or the syndiotacticity expressed in termsof the pentad is not less than 30%;

poly(o-methoxystyrene) in which the syndiotacticity expressed in termsof the diad is not less than 80%, or the syndiotacticity expressed interms of the pentad is not less than 40%, and

poly(p-methoxystyrene) in which the syndiotacticity expressed in termsof the diad is not less than 75%, or the syndiotacticity expressed interms of the pentad is not less than 30%;

When the styrene polymers of the present invention are copolymers, thesyndiotactic arrangement exists not only between the structural units(A) and (A), and between the structural units (B) and (B), but alsobetween the structural units (A) and (B); that is, the styrenecopolymers of the present invention have a cosyndiotactic structure.

The styrene polymers of the present invention may be block polymers,random polymers, alternating monomer polymers, etc.

The styrene polymers of the present invention are not limited to theabove specified styrene polymers and do not have to be a singlecompound. That is, the styrene polymers of the present inventioninclude, as well as the above specified styrene polymers, mixtures ofthe above specified styrene homo-and copolymers and isotactic or atacticstyrene homo-and/or copolymers and the above specified styrene polymerswith isotactic or atactic styrene homo-and copolymers incorporatedtherein.

Copolymers with the styrene polymers of the present inventionincorporated in the chain thereof are also included in the scope of thepresent invention as long as their syndiotacticity falls within theabove-defined range. In addition, the styrene polymers of the presentinvention may be mixtures of styrene polymers having different molecularweights.

The styrene polymers of the present invention have a degree ofpolymerization of not less than 5, preferably not less than 10.

The styrene polymers of the present invention, having the desiredstereoregularity and substituent can be produced by polymerizing thecorresponding monomers, or by applying treatment such as fractionation,blending and organic preparation techniques to polymers produced.

The styrene polymers of the present invention can be produced bypolymerizing styrene monomers such as styrene and styrene derivatives,e.g., alkylstyrene and halogenated styrene in the presence of a catalystcomprising a titanium compound, e.g., titanium halide andalkoxytitanium, and an organoaluminum compound, e.g., alkylaluminoxane.

If the styrene polymer is a copolymer of the present invention, it canbe produced by copolymerizing at least one styrene-based monomerrepresented by the general formula (A'): ##STR7## (wherein R' and m arethe same as defined above) and two or more styrene-based monomersrepresented by the general formula (B'): ##STR8## (wherein R² and n arethe same as defined above) in the presence of a catalyst comprising (a)a titanium compound and (b) a reaction product of an organoaluminumcompound, and water as a a condensing agent.

Styrene polymers produced by the above polymerization method have a highsyndiotacticity which have not yet been obtained, without application oftreatment such as fractionation. Application of fractionation treatmentusing a suitable solvent provides styrene polymers the syndiotacticityof which is nearly 100%. The styrene polymers of the present invention,having the desired tacticity can be produced by blending the abovestyrene polymers having a syndiotacticity of nearly 100% with atactic orisotactic styrene polymers by known techniques. It is well known thatvarious substituents are introduced into automatic rings of styrenepolymers by organic chemical techniques such as chloromethylation. Thestyrene polymers having various substituents in the aromatic ringthereof of the present invention can be prepared by the above methodusing the styrene polymers of the present invention as a base polymerwhile maintaining the tacticity thereof.

The styrene Homo-and Co-polymers of the present invention are novel inthat they have, as described above, a stereoregular molecular structurewhich conventional styrene polymers do not have. Styrene polymersundergoing crystallization are excellent in heat resistance and also inchemical resistance as compared with commonly used atactic polystyrene.Thus these styrene polymers can be used as materials for use inproduction of molded articles which are needed to have high heatresistance and chemical resistance. Styrene polymers in which afunctional substituent is introduced in the benzene ring as a side chaincan be widely used as functional polymers.

CATALYST

The catalyst for preparing syndiotactic polystyrene according to thepresent invention comprises (a) a titanium compound and (b) a reactionproduct of an organoaluminum compound, and water as a condensing agent.

As the titanium component (a), various titanium compounds can be used.Preferably the titanium component (a) is at least one titanium compoundselected from titanium compounds and titanium chelate compoundsrepresented by the general formula (C):

    TiR.sup.3.sub.a R.sup.4.sub.b R.sup.5.sub.c X.sup.1.sub.4-(a+b+c)(C)

or the general formula (D):

    TiR.sup.3.sub.d R.sup.4.sub.e X.sup.1.sub.3-(d+e)          (D)

(wherein R³, R⁴ and R⁵ are each a hydrogen atom, an alkyl group having 1to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, an arylgroup having 6 to 20 carbon atoms, an alkylaryl group having 6 to 20carbon atoms, an arylalkyl group having 6 to 20 carbon atoms, an acyloxygroup having 1 to 20 carbon atoms, a cyclopoentadienyl group, asubstituted cyclopentadienyl group or an indenyl group, X¹ is a halogenatomn, a, b and c are each an integer of 0 to 4, and d and e are each aninteger of 0 to 3).

Representative examples of the alkyl group having 1 to 20 as representedby R³, R⁴ or R⁵ are a methyl group, an ethyl group, a propyl group, abutyl group, an amyl group, an isoamyl group, an isobutyl group, anoctyl group and a 2-ethylhexyl group.

Representative examples of the alkoxy group having 1 to 20 carbon atomsare a methoxy group, an ethoxy group, a propoxy group, a butoxy group,an amyloxy group, a hexyloxy group and a 2-ethylhexyloxy group.

Representative examples of the aryl, alkylaryl or arylalkyl having 6 to20 carbon atoms are a phenyl group, a tolyl group, a xylyl group and abenzyl group. are usually used. Representative examples of theorgano-aluminum compound of the general formula (F) aretrimethylaluminum, triethylaluminum and triisobutylaluminum. Of thesecompounds, trimethylaluminum is most preferred.

The condensing agent to be condensed with the above organoaluminumcompound is water.

An example of the reaction product between an alkylaluminum compound,which is a typical example of the organoaluminum compound component, andwater is alkylaluminoxane represented by the following general formula(G): ##STR9## (wherein R⁹ is a alkyl group having 1 to 8 carbon atoms,and j is a number of 2 to 50).

The reaction between the organoaluminum compound and water is notcritical and can be carried out by known techniques. For example, (1) amethod in which the organoaluminum compound is dissolved in an organicsolvent and then is brought into contact with water; (2) a method inwhich the organoaluminum compound is added at the time of polymerizationand then water is added; and (3) a method in which water ofcrystallization contained in, e.g., metal salts, or water adsorbed onorganic or inorganic substances is reacted with the organoaluminumcompound can be employed.

In the catalyst for use in the process of the present invention theorganoaluminum component (b) can be used as a single compound. Inaddition, the component (b) can be used in admixture with otherorganoaluminum compounds represented by the general formula (F) or otherorganometallic compounds, or can be used in the form that it is adsorbedor deposited on inorganic substances and so forth. formula (F) or otherorganometallic compounds, or can be used in the form that it is adsorbedor deposited on inorganic substances and so forth.

The catalyst for use in the process of the present invention containsthe above components (a) and (b) as main components. In addition to thecomponents (a) and (b), if desired, other catalyst components can beadded.

The ratio of the component (a) to the component (b) in the catalyst ofthe present invention varies with the type of each component, the typeof the styrene starting material, and other conditions, and thus cannotbe determined unconditionally. Usually, however, the molar ratio ofaluminum in the component (b) to titanium in the component (a), i.e.,aluminum/titanium, is preferably 1:1 to 1×10⁶ :1 and more preferably10:1 to 1×10⁴ :1.

In accordance with the process of the present invention, at least onestyrene-based monomer represented by the general formula (A') and atleast one styrene-based monomer represented by the general formula (B')are copolymerized. The styrene-based monomer represented by the generalformula (A') forms a first structural unit of the general formula (A),and the styrene-based monomer represented by the general formula (B')forms the structural unit of the general formula (B) in the course ofthe copolymerization reaction. Thus, as representative examples of thestyrene-based monomers represented by the general formulae (A') and(B'), compounds corresponding to the representative examples of thestructural units (A') and (B) can be listed (both of which arerepresented by general formula (I)).

In accordance with the process of the present invention, two or morestyrene-based monomers as described above are copolymerized in thepresence of a catalyst containing the above components (a) and (b). Thispolymerization may be bulk polymerization or solution polymerization. Inthe solution polymerization, as the solvent, aliphatic hydrocarbons suchas pentane, hexane and heptane, alicyclic hydrocarbons such ascyclohexane, aromatic hydrocarbons such as benzene, toluene and xylene,and so on can be used. The polymerization temperature is not critical;it is usually 0° to 90° C. and preferably 20° to 70° C.

In order to control the molecular weight of the sytrene copolymer to beformed, it is effective to perform the copolymerization reaction in thepresence of hydrogen. In this case, the partial pressure of hydrogen isappropriately chosen within the range of 0.01 to 50 kg/cm².

A representative example of the acyloxy group having 1 to 20 carbonatoms is a heptadecylcarbonyloxy group.

Representative examples of the substituted cyclopentadienyl group are amethylcyclopentadienyl group, a 1,2-dimethylcyclopentadienyl group and apentamethylcyclopentadienyl group.

In the general formulae (C) and (D), R³, R⁴ and R⁵ may be the same ordifferent.

X¹ is a halogen atom, i.e., chlorine, bromine, iodine or fluorine.

a, b and c are each an integer of 0 to 4.

d and e are each an integer of 0 to 3.

Representative examples of the tetravalent titanium compounds andtitanium chelate compounds represented by the general formula (C) aremethyltitanium trichloride, titanium tetramethoxide, titaniumtetramethoxide, titanium monoisopropoxy trichloride, titaniumdiisopropoxy dichloride, titanium triisopropoxy monochloride,tetra(2-ethylhexyloxy)titanium, cyclopentadienyltitanium trichloride,biscyclopentadienyltitanium dichloride, titanium tetrachloride, titaniumtetrabromide, bis(2,4-pentanedionate)titanium oxide,bis(2,4-pentanedionate)titanium dichloride, andbis(2,4-pentanedionate)titanium dibutoxide.

In addition, as the titanium component (a), condensed titanium compoundsrepresented by the general formula (E): ##STR10## (wherein R⁶ and R⁷ areeach a halogen atom, an alkoxy group having 1 to 20 carbon atoms, or anacyloxy group, and k is a number of 2 to 20) can be used.

The above titanium compounds can be used in a state that they areadsorbed or deposited on a carrier such as magnesium compounds, silicaand alumina, or in the form of complexes with esters or ethers, forexample.

Representative examples of the trivalent titanium compounds representedby the above general formula (D) as the titanium component (a) aretitanium trihalide such as titanium trichloride andcyclopentadienyltitanium compounds such as cyclopentadienyltitaniumdichloride. In addition, compounds resulting form reduction oftetravalent titanium compounds can be used. These trivalent titaniumcompounds may be used in the form of complexes with esters or ethers,for example.

The component (b) to be used in combination with the above titaniumcomponent (a) is prepared by reacting organoaluminum compound and water.

As the organoaluminum compound to be used in the component (b),organoaluminum compounds (trialkylaluminum) represented by the generalformula (F):

    AlR.sup.8.sub.3                                            (F)

(wherein R⁸ is an alkyl group having 1 to 8 carbon atoms)

HOMOPOLYMERS EXAMPLE 1

(1) Preparation of Catalyst Component

Trimethylaluminum (47.4 milliliters (ml): 492 millimoles (mmol)) wasadded to 200 ml of toluene as a solvent, and then 35.5 grams (g) (142mmol) of copper sulfate pentahydrate (CuSO₄.5H₂ O) was added thereto.These ingredients were reacted at 20° C. for 24 hours. When the reactionwas completed, the toluene solvent was removed by filtration to obtain12.4 g of methylaluminoxane.

(2) Production of Polystyrene

A mixture of 100 ml of toluene and 40 mmol (calculated as an aluminumatom) of methylaluminoxane was placed in a glass vessel (internalvolume: 500 ml) equipped with a stirrer, and then 0.05 mmol. ofcyclopentadienyltitanium trichloride was added thereto. Subsequently 180ml of styrene was added at 20° C. and polymerized for 1 hour. Thenmethanol was poured to terminate the polymerization reaction, and amixture of hydrochloric acid and methanol was added to decompose thecatalyst component.

The yield of polystyrene was 16.5 g. The polystyrene had a weightaverage molecular weight of 280,000 and a number average molecularweight of 57,000. The polystyrene was extracted with methyl ethyl ketoneas a solvent for 4 hours by the use of a Soxlet extractor. The insolublesolids content was 97 percent by weight (wt %). This methyl ethylketone-insoluble polystyrene had a melting point of 260° C. and aspecific gravity of 1.043.

In connection with the methyl ethyl ketone-insoluble polystyrene, a ¹³C-NMR spectrum (signal of C₁ carbon of the aromatic ring) is shown inFIG. 1 (indicated by the symbol (a)), a ¹³ C-NMR spectrum (signal ofmethine methylene carbon) is shown in FIG. 2 (indicated by the symbol(a)), a ¹ H-NMR spectrum (proton nuclear magnetic resonance spectrum) isshown in FIG. 3, (indicated by the symbol (a)), an X-ray diffractionpattern is shown in FIG. 4 (indicated by the symbol (a)), and aninfrared absorption spectrum is shown in FIG. 5 (indicated by the symbol(a)).

COMPARATIVE EXAMPLE 1

Styrene was radical-polymerized at 0° C. by the use of an organicperoxide to produce atactic polystyrene. This polystyrene was extractedwith methyl ethyl ketone in the same manner as in Example 1 (2). It wasfound that the whole of the polystyrene was extracted. This polystyrenehad a glass transition temperature of 100° C. and a specific gravity of1.05.

In connection with this atactic polystyrene, a ¹³ C-NMR spectrum (signalof C₁ carbon of the aromatic ring) is shown in FIG. 1(b), a ¹³ C-NMRspectrum (signal of methine methylene carbon) is shown in FIG. 2(b), andan infrared absorption spectrum is shown in FIG. 5(b).

COMPARATIVE EXAMPLE 2

A titanium catalyst component with a titanium compound deposited thereonwas prepared by reacting 10.0 g of magnesium diethoxide and 50 ml oftitanium tetrachloride. Then 1.0 mmol of the titanium catalyst componentthus prepared and 10 mmol of triethylaluminum were combined together toprepare a catalyst. Using this catalyst, 100 ml of styrene waspolymerized in heptane as a solvent at 70° C. for 2 hours to yield 48.7g of isotactic polystyrene having a weight average molecular weight of1,000,000. This polystyrene was extracted in the same manner as inExample 1 (2). The insoluble solids content was 96 wt %.

In connection with this methyl ethyl ketone-insoluble polystyrene, a ¹³C-NMR spectrum (signal of C₁ carbon of the aromatic ring) is shown inFIG. 1(c), a ¹³ C-NMR (signal of methine methylene carbon) is shown inFIG. 2(c), a ¹ H-NMR spectrum is shown in FIG. 3(b), a X-ray diffractionpattern is shown in FIG. 4(b), and an infrared absorption spectrum isshown in FIG. 5(c).

Based on the analytical data of the polystyrene obtained in Example 1(2) and the analytical data of the atactic polystyrene obtained inComparative Example 1, and the analytical data of the isotacticpolystyrene obtained in Comparative Example 2, it was confirmed that thepolystyrene of Example 1 (2) had a syndiotactic structure.

(1) ¹³ C-NMR data

(i) Signal of C₁ carbon of the aromatic ring

It is well known that splitting of the aromatic ring C₁ carbon signal isascribable to a polymer microstructure. The value found in theliterature, and the values actually measured for the polystyrene ofExample 1, atactic polystyrene of Comparative Example 1 and isotacticpolystyrene of Comparative Example 2 (FIG. 1(a, (b), (c)) are tabulatedin Table 1.

It can be seen from the results of Table 1 that the polystyrene ofExample 1 has a syndiotactic structure, and the syndiotacticity in termsof the racemic pentad as determined from the peak area of FIG. 1(a) isnot less than 96%; that is, the polystyrene of Example 1 had a tacticityof nearly 100%.

                  TABLE 1                                                         ______________________________________                                                Type of Polystyrene                                                                     Value                                                                 Atactic of the                                                                Poly-   Litera- Polystyrene                                                                             Isotactic                                 Ascription*.sup.1                                                                       styrene ture*.sup.2                                                                           of Example 1                                                                            Polystyrene                               ______________________________________                                        mmmm      --      --      --        146.44                                    mmmr      146.27  146.23  --        --                                        rmmr      146.00  146.03  --        --                                        mmrm      145.85  145.80  --        --                                        mmrr      --      --      --        --                                        rmrm      145.60  145.63  --        --                                        rrmr      --      --      --        --                                        rr        145.32  145.32  145.35    --                                        ______________________________________                                         *.sup.1 m represents a structural unit of                                     ##STR11##                                                                     and r represents a structural unit of                                         ##STR12##                                                                     *.sup.2 Value shown in H. Sato & Y. Tanaka, J. Polym. Sci., Polym. Phys.      Ed., 21, 1667-1674 (1983).                                               

(ii) Methine methylene carbon signal

It is also well known that splitting of the methine methylene carbonsignal is ascribable to a polymer microstructure. In the case ofpolystyrene, there are many literatures reporting the ascription of thesplitting. The value found in the literature, and the values actuallymeasured for the polystyrene of Example 1 atactic polystyrene ofComparative Example 1 and isotactic polystyrene of Comparative Example 2(FIG. 2(a), (b), (c)) are tabulated in Table 2.

                  TABLE 2                                                         ______________________________________                                               Type of Polystyrene                                                                                  Poly-                                                                         styrene                                                  Atactic   Value of the                                                                             of Exam-                                                                             Isotactic                                Ascription*.sup.1                                                                      Polystyrene                                                                             Literature*.sup.2                                                                        ple 1  Polystyrene                              ______________________________________                                        mrmm     46.73     46.73      --     --                                       mrmrr    46.65     46.44      --     --                                       rrmrr    46.19     46.22      --     --                                       mrrrm    45.79     45.61      --     --                                       rrrrm    45.20     45.22      --     --                                       rrrrr    44.70     44.95      44.74  --                                       mmr      --        44.79      --     --                                       mrrmr    44.05     44.05      --     --                                       mrrmm    --        --         --     --                                       rrrmr    43.53     43.59      --     --                                       rrrmm    --        --         --     --                                       mmm      --        --         --     43.34                                    rmrmr    --        42.70      --     --                                       mmrmr    --        42.66      --     --                                       mmrmm    --        42.55      --     --                                       ______________________________________                                         *.sup.1, *.sup.2 : Same as in Table 1.                                   

The figures in the table are expressed in the unit of ppm(tetramethylsilane (TMS) standards). It can be seen from the results ofTable 2 that the polystyrene of Example 1 is syndiotactic polystyrene,and its syndiotacticity is nearly 100% because the signal of methylenecarbon exhibits a single peak.

(2) ¹ H-NMR data

It is well known as described in S. Brownstein, S. Bywater & D. T.Worsford, J. Phys. Chem., 66, 2067 (1962) that the ¹ H-NMR spectrumprovides an information concerning the microstructure like the ¹³ C-NMRspectrum.

The methine proton signal of the polystyrene of Example 1 shows thatwhen FIG. 3(a) and (b) are compared, the methine proton of thepolystyrene of Example 1 appears a higher magnetic field as comparedwith that of the isotactic polystyrene of Comparative Example 2; thatis, the polystyrene of Example 1 is apparently different from theisotactic polystyrene of Comparative Example 2. Furthermore, thespectrum of the polystyrene of Example 1 shows considerable finestructure. This fact also confirms that the polystyrene of Example 1 isdifferent from at actic polystyrene because the spectrum of the atacticpolystyrene does not show a fine structure (see F. A. Bovey & F. P.Hood, III, J. Chem. Phys. 38, 1026 (1963). Moreover, there were observedonly one kind of methine proton and of methylene proton in the molecularchain. Based the above data, it was judged that the polystyrene ofExample 1 has a nearly 100% syndiotactic structure.

Based on the results of (1) and (2) above, it was confirmed that thepolystyrene of Example 1 was a polymer having a steric configurationcomprising not less than 96% in terms of the racemic pentad; that is, apolymer comprising nearly 100% of a syndiotactic structure. (3) X-raydiffraction pattern

The polystyrene of Example 1 was crystalline. The X-ray diffractionpattern (FIG. 4(a)) of the crystalline polystyrene is quite differentfrom that of the isotactic polystyrene (FIG. 4(b)) (G. Natta & P.Corradini, Nuovo Cimento, 15, Suppl. 1, 40 (1960)). Thus it can be seenthat the polystyrene of Example 1 is different in crystalline structurefrom isotactic polystyrene.

From the results of FIG. 4(a), it was found that the identity period ofthe polystyrene of Example 1 was 5.04 Å. This identity period suggeststhat the polymer chain is in a zig-zag structure and phenyl rings aredisposed alternately. This confirms that the polystyrene of Example 1has a syndiotactic structure. ##STR13##

(4) Infrared absorption spectrum

Peaks of the spectra shown in FIG. 5(a), (b), (c) are shown in Table 3.

                  TABLE 3                                                         ______________________________________                                                      Wave Number (cm.sup.-1)                                                       1364  1312   1297    1185 583                                   ______________________________________                                        Polystyrene of Example 1                                                                      x       x      x     ∘                                                                      x                                   Isotactic Polystyrene                                                                         ∘                                                                         ∘                                                                        ∘                                                                       ∘                                                                      ∘                       Atactic Polystyrene                                                                           ∘                                                                         ∘                                                                        ∘                                                                       ∘                                                                      x                                   ______________________________________                                         ∘: Absorption                                                     x: No absorption                                                         

The polystyrene of Examples 1 has a characteristic absorption peak at1220 cm⁻¹ which cannot be found in polystyrene having an isotactic oratactic structure.

(5) Melting point

The melting point of the polystyrene of Example 1 was 260°-270° C.,which is much higher than that (220°-230° C.) of isotactic polystyrene.

(6) Tacticity of extract after extraction with methyl ethyl ketone

In determining the stereoregularity of polystyrene, the following methodis generally employed.

Polystyrene is extracted with methyl ethyl ketone as a solvent by theuse of a Soxlet extractor. If the polystyrene is insoluble, it isdetermined to be isotactic polystyrene, and if soluble, it is determinedto be atactic polystyrene (T. Nakada, Y. Kinosita, T. Ohtu & M. Imoto,Kougyo Kagaku, 68, 858-864 (1965)).

A methyl ethyl ketone-insoluble portion of the polystyrene of Example 1had a syndiotactic structure, and a methyl ethyl ketone-soluble portionalso has a syndiotacticity of not less than 82%.

Styrene (100 ml) was polymerized at 50° C. for 8 hours in the presenceof a catalyst comprising 1 mmol of titanium tetrachloride and 40 mmol ofmethylaluminoxane. Thereafter, the same procedure as in Example 1 (2)was repeated to form 0.1 g of polystyrene.

For the polystyrene thus obtained, the syndiotacticity was such that theracemic pentad of ¹³ C-NMR was not less than 36%, the weight averagemolecular weight (Mw) was 544,000, and the number average molecularweight (Wn) was 223,000.

In the extraction of the polystyrene with methyl ethyl ketone, 79 wt %of the polystyrene was extracted. For the extraction residue, thesyndiotacticity was such that the racemic pentad of ¹³ C-NMR was 86%,the weight average molecular weight (Mw) was 678,000 and the numberaverage molecular weight (Mn) was 272,000. The syndiotacticity of theabove extract was such that the racemic pentad of ¹³ C-NMR was 23%. Thisis similar to a tacticity of the usual radical polymerized polystyrene.

EXAMPLE 3

The procedure of Example 2 was repeated wherein the amount of titaniumtetrachloride as a catalyst component was changed to 0.05 mmol, theamount of styrene used was changed to 180 ml, and the polymerizationtime was changed to 2 hours. In this was, 6.7 g of polystyrene wasproduced.

In the extraction of the polystyrene thus obtained with methyl ethylketone, 8 wt % of the polystyrene was extracted. For the extractionresidue; that is polystyrene remaining after the extraction, thesyndiotacticity was not less than 99%, the weight average molecularweight (Mw) was 348,000 and the number average molecular weight (Mn) was156,000.

EXAMPLE 4

The procedure of Example 1 was repeated wherein 1 mmol ofisopropoxytitanium trichloride was used in place of titaniumtetrachloride as a catalyst component and the polymerization time waschanged to 2 hours. In this way, 0.4 g of polystyrene was produced. Forthe polystyrene thus produced, the syndiotacticity was such that theracemic pentad of ¹³ C-NMR was 96%, the weight average molecular weight(Mw) was 92,000 and the number average molecular weight (Mn) was 31,000.

In the extraction of the above polystyrene with methyl ethyl ketone, 58wt % of the polystyrene was extracted. For the extraction residue; thatis, polystyrene remaining after the extraction, the syndiotacticity wassuch that the racemic pentad of ¹³ C-NMR was 96%, the weight averagemolecular weight (Mw) was 100,000 and the number average molecularweight (Mn) was 36,000. The syndiotacticity of the extract was such thatthe racemic pentad was 23%.

EXAMPLE 5

Polystyrene was produced in the same manner as in Example 2 except thata catalyst comprising 0.02 mmol of ethoxytitanium trichloride and 10mmol of methylaluminoxane was used and polymerization was performedunder the conditions shown in Table 4. The polystyrene thus produced wasextracted with methyl ethyl ketone in the same manner as in Example 2.Properties of the polystyrene are shown in Table 4.

EXAMPLE 6

Polystyrene was produced in the same manner as in Example 2 except thata catalyst comprising 0.2 mmol (calculated as titanium tetrachloride) ofmagnesium diethoxide with titanium tetrachloride deposited thereon in anamount of 146 mg/g carrier and 10 mmol of methylaluminoxane was used andpolymerization was performed under the conditions shown in Table 4. Thepolystyrene thus produced was extracted with methyl ethyl ketone.Properties of the polystyrene are shown in Table 4.

EXAMPLE 7

Polystyrene was produced in the same manner as in Example 2 except thata catalyst comprising 0.2 mmol (calculated as tetraethoxytitanium) ofmagnesium chloride with titanium tetraethoxide deposited thereon in anamount of 80 mg/g carrier and 10 mmol of methylaluminoxane was used andpolymerization was performed under the conditions shown in Table 4. Thepolystyrene thus produced was extracted with methyl ethyl ketone in thesame manner as in Example 2. Properties of the polystyrene are shown inTable 4.

EXAMPLE 8

Polystyrene was produced in the same manner as in Example 2 except thata catalyst comprising 0.02 mmol (calculated as titanium) of magnesiumchloride with an excess of titanium tetrachloride deposited thereon and10 mmol of methylaluminoxane was used and polymerization was performedunder the conditions shown in Table 4. The polystyrene thus produced wasextracted with methyl ethyl ketone in the same manner as in Example 2.Properties of the polystyrene are shown in Table 4.

EXAMPLE 9

Polystyrene was produced in the same manner as in Example 2 except thata catalyst comprising 0.02 mmol (calculated as titanium) of magnesiumchloride with titanium tetrachloride and ethyl benzoate depositedthereon and 10 mmol of methylaluminoxane was used and polymerization wasperformed under the conditions shown in Table 4. The polystyrene thusproduced was extracted with methyl ethyl ketone in the same manner as inExample 2. Properties of the polystyrene are shown in Table 4.

EXAMPLE 10

Polystyrene was produced in the same manner as in Example 2 except thata catalyst comprising 0.02 mmol of titanium trichloride and 20 mmol ofmethylaluminoxane was used and polymerization was performed under theconditions shown in Table 4. The polystyrene thus produced was extractedwith methyl ethyl ketone in the same manner as in Example 2. Propertiesof the polystyrene are shown in Table 4.

EXAMPLE 11

Polystyrene was produced in the same manner as in Example 2 except thata catalyst comprising 1 mmol of titanium tetrachloride, 1 mmol ofvanadyl tributoxide (VO(O.C₄ H₉)₃) and 40 mmol of methylaluminoxane wasused and polymerization was performed under the conditions shown inTable 4. The polystyrene thus produced was extracted with methyl ethylketone in the same manner as in Example 2. Properties of the polystyreneare shown in Table 4.

EXAMPLES 12 AND 13

Polystyrene was produced in the same manner as in Example 2 except thata catalyst comprising 1 mmol of isopropoxytitanium chloride, 1 mmol ofvanadyl tributoxide and 40 mmol of methylaluminoxane was used andpolymerization was performed under the conditions shown in Table 4. Thepolystyrene thus produced was extracted with methyl ethyl ketone in thesame manner as in Example 2. Properties of the polystyrene are shown inTable 4.

EXAMPLES 14 TO 16

Polystyrene was produced in the same manner as in Example 2 except thata catalyst comprising 0.05 mmol of titanium tetraethoxide and 5 mmol ofmethylaluminoxane was used and polymerization was performed under theconditions shown in Table 4. The polystyrene thus produced was extractedwith methyl ethyl ketone in the same manner as in Example 2. Propertiesof the polystyrene are shown in Table 4.

EXAMPLE 17

Polystyrene was produced in the same manner as in Example 2 except thata catalyst comprising 0.05 mmol of titanium tetraethoxide and 10 mmol ofmethylaluminoxane was used and polymerization was performed under theconditions shown in Table 4. The polystyrene thus produced was extractedwith methyl ethyl ketone in the same manner as in Example 2. Propertiesof the polystyrene are shown in Table 4.

EXAMPLES 18 TO 20

Polystyrene was produced in the same manner as in Example 2 except thata catalyst comprising 0.05 mmol of titanium tetraethoxide and 25 mmol ofmethylaluminoxane was used and polymerization was performed under theconditions shown in Table 4. The polystyrene thus produced was extractedwith methyl ethyl ketone in the same manner as in Example 2. Propertiesof the polystyrene are shown in Table 4.

EXAMPLE 21

Polystyrene was produced in the same manner as in Example 2 except thata catalyst comprising 1 mmol of titanium tetraisoproxide, 1 mmol ofvanadyl tributoxide and 40 mmol of methylaluminoxane was used andpolymerization was performed under the conditions shown in Table 4. Thepolystyrene thus produced was extracted with methyl ethyl ketone in thesame manner as in Example 2. Properties of the polystyrene are shown inTable 4.

EXAMPLE 22

A styrene-p-methylkstyrene copolymer was produced in the same manner asin Example 2 except that a catalyst comprising 0.02 mmol ofcyclopentadienyltitanium trichloride and 10 mmol of methylaluminoxanewas used, and a mixture of styrene and p-methylstyrene was used as thestarting material and polymerized under the conditions shown in Table 4.The copolymer thus produced was extracted with methyl ethyl ketone inthe same manner as in Example 2. Properties of the copolymer are shownin Table 4.

EXAMPLE 23

Poly)p-methylstyrene) was produced in the same manner as in Example 2except that a catalyst comprising 0.025 mmol of cyclopentadienyltitaniumtrichloride and 40 mmol of methylaluminoxane was used, andp-methylstyrene was used as the starting material and polymerized underthe conditions shown in Table 4. The poly(p-methylstyrene) thus producedwas extracted with methyl ethyl ketone in the same manner as in Example2. Properties of the poly(p-methylstyrene) are shown in Table 4.

A ¹³ C-NMR spectrum (aromatic carbon C₁ carbon signal) of thepoly(p-methylstyrene) is shown in FIG. 1(d); a ¹³ C-NMR spectrum(methine methylene carbon signal) is shown in FIG. 2(d); a ¹ H-NMRspectrum is shown in FIG. 3(c); an X-ray diffraction pattern is shown inFIG. 4(c); and an infrared absorption spectrum is shown in FIG. 5(d).

EXAMPLE 24

Poly(m-methylstyrene) was produced in the same manner as in Example 2except that a catalyst comprising 0.05 mmol of cyclopentadienyltitaniumtrichloride and 30 mmol of methylaluminoxane was used, andm-methylstyrene was used as the starting material and polymerized underthe conditions shown in Table 4. The poly(m-methylstyrene) thus producedwas extracted with methyl ethyl ketone in the same manner as in Example2. Properties of the poly(m-methylstyrene) are shown in Table 4.

A ¹³ C-NMR (aromatic ring C₁ carbon signal) of the poly(m-methylstyrene)is shown in FIG. 1(e).

EXAMPLE 25

Poly(p-tert-butylstyrene) was produced in the same manner as in Example2 except that a catalyst comprising 0.05 mmol ofcyclopentadienyltitanium trichloride and 30 mmol of methylaluminoxanewas used, and p-tert-butylstyrene was used as the starting material andpolymerized under the conditions shown in Table 4. Thepoly(p-tert-butylstyrene) thus produced was extracted with methyl ethylketone in the same manner as in Example 2. Properties of thepoly(p-tert-butylstyrene) are shown in Table 4.

A ¹³ C-NMR spectrum (aromatic ring C₁ carbon signal) of thepoly(p-tert-butylstyrene) is shown in FIG. 1(f).

EXAMPLE 26

Poly(p-chlorostyrene) was produced in the same manner as in Example 2except that a catalyst comprising 0.05 mmol of cyclopentadienyltitaniumtrichloride and 40 mmol of methylaluminoxane was used, p-chlorostyrenewas used as the starting material and polymerized under the conditionsshown in Table 4. The poly(p-chlorostyrene) thus produced was extractedwith methyl ethyl ketone in the same manner as in Example 2. Propertiesof the poly(p-chlorostyrene) are shown in Table 4.

A ¹³ C-NMR spectrum (aromatic ring C₁ carbon signal) of thepoly(p-chlorostyrene) is shown in FIG. 1(g). For comparison, a ¹³ C-NMRspectrum (aromatic ring C₁ carbon signal of atacticpoly(p-chlorostyrene) is shown in FIG. 1(h).

EXAMPLE 27

Poly(m-chlorostyrene) was produced in the same manner as in Example 2except that a catalyst comprising 0.05 mmol of titanium tetraethoxideand 5 mmol of methylaluminoxane was used, and m-chlorostyrene was usedas the starting material and polymerized under the conditions shown inTable 4. The poly(m-chlorostyrene) thus produced was extracted withmethyl ethyl ketone in the same manner as in Example 2. Properties ofthe poly(m-chlorostyrene) are shown in Table 4. A ¹³ C-NMR spectrum(aromatic ring C₁ carbon signal) of the poly(m-chlorostyrene) is shownin FIG. 1(i).

EXAMPLE 28

Poly(p-fluorostyrene) was produced in the same manner as in Example 2except that a catalyst comprising 0.05 mmol of cyclopentadienyltitaniumtrichloride and 30 mmol of methylaluminoxane was used, andp-fluorostyrene was used as the starting material and polymerized underthe conditions shown in Table 4. The poly(p-fluorostyrene) thus producedwas extracted with methyl ethyl ketone in the same manner as in Example2. Properties of the poly(p-fluorostyrene) are shown in Table 4. A ¹³C-NMR spectrum (aromatic ring C₁ carbon signal) of thepoly(p-fluorostyrene) is shown in FIG. 1 (j).

    TABLE 4      Properties of Polymer Monomer Solvent Polymerization Conditions Polymer M     olecular Weight  Example  Type Amount (ml) Type Amount (ml) Temp.     (°C.) Time (hours) Yield (g) Extraction Residue (wt %) Mw Mn     Syndiotactivity*.sup.1 Remarks        1  Styrene  180 Toluene 100 20 1 16.5 97 280,000  57,000  96< Product                   (m.p. 260  2  "  100 " 100 50 8 0.2 21 678,000 272,000 86     Extraction               residue  3  "  180 " 100 50 2 6.7 92 348,000     156,000 99 Extraction               residue  4  "  100 " 100 50 2 0.4 42     100,000  36,000 96 Extraction               residue  5  "  50 " 100 50 2     0.67 75 388,000 124,000 91 Extraction               residue  6  "  50 "     100 50 2 0.42 32 239,000 115,000 96 Extraction               residue  7     "  50 " 100 50 2 1.2 88 256,000 121,000 97 Extraction     residue  8  "  50 " 100 50 2 1.08 70 517,000 220,000 74 Extraction             residue      9  "  50 " 100 50 2 1.63 84 600,000 230,000 38 Extraction     residue 10  "  50 " 100 50 2 0.41 30 871,000 413,000 58 Extraction             residue 11  "  50 " 200 50 2 0.35 30 174,000      68,000 75 Extraction               residue 12  "  50 " 200 50 2 0.5 41     204,000  22,000 85 Extraction               residue 13  "  100 " 100 50     2 0.5 41 163,000  19,000 31 Extraction               residue 14  "  150     "  20 20 6 3.0 84 2,480,000   995,000  96< Extraction     residue 15  "  150 "  20 30 7 8.9 99 1,893,000   773,000  96< Extraction                   residue 16  "  150 "  20 40 3 12.5 96 1,244,000   358,000     96< Extraction               residue 17  "  150 "  20 50 4 15.7 94     613,000 288,000  96< Extraction               residue 18  "  50 Benzene     100 50 4 1.9 89 301,000  96,000  96< Extraction               residue 19      Styrene  50 p-Xylene 100 50 2 1.8 92 201,000 101,000  96< Extraction                residue 20  "  75 Toluene  75 50 6 3.3 86 407,000 193,000     96< Extraction               residue 21  "  100 " 200 50 3.5 0.4 11     9,700  3,900 8 Extraction               residue   "  53.1 22     " 100     50 2 17.8 76  79,000  45,000  .sup.      72*.sup.2 Extraction   p-Methyl-styrne  5.2          residue 23     p-Methyl-styrne  80 " 100 50 1 16.0 55  48,000  23,000 94 Extraction     residue               (m.p. 173° C.)             33,000  14,000     -- Extraction residue               (m.p. 168°      C.) 24  m-Methyl-styrene  17 " 100 50 3 15.1 98  59,000  26,000 92     Extraction residue               (m.p. 206°      C.) 25  p-tert-Butyl-styrene  27 g " 100 50 4 25.3 99  71,000  21,000     94 Extraction residue               (m.p. 310°      C.) 26  p-Chloro-styrene   40 " 100 20 2 1.7 90  20,000  2,000 91     Extraction residue               (m.p. 298°      C.) 27  m-Chloro-styrene  25 " 100 50 9 1.8 51  47,000  13,000 80     Extraction residue 28  p-Fluoro-styrene 24 " 100 50 5 0.2 --  29,000     88,000 70 Extraction residue     *.sup.1 Expressed in the racemic pentad.     *.sup.2 Expressed in the racemic pentad in the styrene structure unit.

COPOLYMERS ("C") Examples below) EXAMPLE 1 C

(1) Preparation of Organoaluminum Compound Component (b) 47.4 ml (0.492mol) of trimethylaluminum and 35.5 g (0.142 mol) of copper sulfatepentahydrate were reacted at 20° C. for 24 hours in 200 ml of a toluenesolvent, and then solids were removed to obtain a toluene solutioncontaining 12.4 g of methylaluminoxane as the organoaluminum compoundcomponent (b). The molecular weight of the methylaluminoxane asdetermined by the benzene cryoscopic method was 721.

(2) Production of Styrene/p-Methylstyrene Copolymer 60 ml of toluene and5 mmol (as aluminum atom) of the methylaluminoxane obtained in (1) abovewere placed in a 500-mililiter glass vessel equipped with a stirrer, andthen 0.05 mmol of tetraethoxytitanium was added thereto. The resultingsolution was heated. At 50° C., a mixture of 475 mmol of styrene and 25mmol of p-methylstyrene was added, and then polymerization was performedfor 2 hours. At the end of the time, methanol was injected to stop thereaction. Then a mixture of hydrochloric acid and methanol was added todecompose the catalyst component. The yield of the styrene copolymerthus obtained was 8.2 g.

The styrene copolymer was introduced in a Soxhlet extractor andextracted with methyl ethyl ketone for 4 hours. The insoluble contentwas 99 wt %. For this methyl ethyl ketone-insoluble styrene copolymer,the p-methylstyrene content was 7 mol %, the weight average molecularweight was 360,000, the number average molecular weight was 200,000, andthe melting point was 246° C.

Aromatic ring C₁ carbon signals of the ¹³ C-NMR spectrum (a nuclearmagnetic resonance spectrum using carbon isotope) of the above methylethyl ketone-insoluble styrene copolymer are shown in FIG. 1A(a₁);methine-methylene carbon signals of the ¹³ C-NMR spectrum, in FIG.1A(a₂); and the ¹ H-NMR spectrum (a proton nuclear magnetic resonancespectrum), in FIG. 1A(b).

COMPARATIVE EXAMPLE 1C

A monomer mixture of styrene and p-methylstyrene (95:5 by mol) waspolymerized at 60° C. using an organic peroxide to obtain an atacticstyrene copolymer. This styrene copolymer was wholly soluble in methylethyl ketone, contained 6 mol % of p-methylstyrene, and had no meltingpoint and had a glass transition temperature of 83° C.

Aromatic ring C₁ carbon signals of the ¹³ C-NMR spectrum of the abovestyrene copolymer are shown in FIG. 2A.

COMPARATIVE EXAMPLE 2C

In the presence of a catalyst consisting of 2.5 mmol of a titaniumcatalyst component which had been prepared by reacting 10.0 g ofmagnesium ethoxide and 50 ml of titanium tetrachloride, 12.5 mmol oftriethylaluminum and 12.5 mmol of diethylaluminum chloride, 190 mmol ofstyrene and 10 mmol of p-methylstyrene were polymerized 50° C. for 2hours in a heptane solvent to obtain 3.19 g of a copolymer. Thiscopolymer was extracted with methyl ethyl ketone in the same manner asin Example 1C(2) to obtain an isotactic styrene copolymer which wasinsoluble in methyl ethyl ketone. This copolymer contained 7 mol % ofp-methylstyrene and had a melting point of 217° C.

Aromatic ring C₁ carbon signals of the ¹³ C-NMR spectrum of the abovecopolymer are shown in FIG. 3A.

As described in Japanese Patent Application Laid-open No. 104318/1987,the melting points of syndiotactic polystyrene and syndiotacticpoly(p-methylstyrene) are 260°-270° C. and 173° C., respectively.

Aromatic C₁ carbon signals of the ¹³ C-NMR spectra of the syndiotacticpolystyrene and the syndiotactic poly(p-methylstyrene) are shown in FIG.4A(a₁) and 4A(a₂), respectively; methine-methylene carbon signals of the¹³ C-NMR spectra of the syndiotactic polystyrene and the syndiotacticpoly(p-methylstyrene) are shown in FIG. 5A(a₁) and FIG. 5A(a₂),respectively; and ¹ H-NMR spectra of the syndiotactic polystyrene andthe syndiotactic poly(p-methylstyrene) are shown in FIG. 4A(b) and FIG.5A(b), respectively.

Based on the analytical results of the above copolymer, the analyticalresults of the atactic styrene copolymer obtained in Comparative Example1C and of the isotactic styrene copolymer obtained in ComparativeExample 2C, and further by comparing with the syndiotactic polystyreneand syndiotactic poly(p-methylstyrene) as described in Japanese PatentApplication Laid-open No. 104818/1987, it was confirmed that the styrenecopolymer obtained in Example 1C had a cosyndiotactic structure

(1) ¹³ C-NMR Analysis

(i) Aromatic Ring C₁ Carbon Signals

It is well known that the splitting of aromatic ring C₁ carbon signalsis ascribable to a polymer microstructure. The found values of thestyrene copolymer obtained in Example 1, the atactic styrene copolymerobtained in Comparative Example 1 and the isotactic styrene copolymerobtained in Comparative Example 2C, and the values of the syndiotacticpolystyrene and syndiotactic poly(p-methylstyrene) as described inJapanese Patent Application Laid-open No. 104818/1987 are summarized inTable 1C.

The C₁ carbon signals of the styrene polymer in the styrene copolymerobtained in Example 1C were at 145.11 ppm and 145.22 ppm. The signal at145.11 ppm indicates the syndiotactic chain of styrene pendant. On theother hand, the signal at 145.22 ppm was not found in the copolymers ofComparative Examples 1C and 2C, it is a signal ascribable to theco-syndiotactic structure. The C₁ carbon signal of p-methylstyrene ofthe styrene copolymer obtained in Example 1C was at 142.9 ppm. Sincethis signal appeared at a high magnetic field as compared with those ofthe copolymer of Comparative Example 2C and of syndiotacticpoly(p-methylstyrene) it was confirmed that the styrene copolymer had aco-syndiotactic structure.

(ii) Methine-Methylene Carbon Signals

It is known that he methine-methylene carbon signal corresponds to themicrostructure of a polymer. The methylene signal of the styrenecopolymer obtained in Example 1C, the methine signal of the styreneportion, and the methine signal of the p-methylstyrene portion were at44.69 ppm, 41.08 ppm and 40.65 ppm, respectively. As can be seen bycomparison of syndiotactic polystyrene with syndiotacticpoly(p-methylstyrene), it was confirmed that the styrene copolymerobtained in Example 1C had a syndiotactic structure.

(2) ¹ H-NMR Analysis

In the styrene copolymer obtained in Example 1C, the syndiotacticpolystyrene and the syndiotactic poly(p-styrene), only one signal wasdetected for each of methine and methylene proton in the polymer chain.Thus it was confirmed that 100% of the styrene copolymer was of thesyndiotactic structure.

(3) Melting Point

The melting point of the styrene copolymer obtained in Example 1C was246° C., which was intermediate between the melting point (260°-270° C.)of the syndiotactic polystyrene and the melting point (173° C.) of thesyndiotactic poly(p-methylstyrene), and which was higher than themelting point (217° C.) of an equimolar amount ofp-methylstyrene-containing isotactic polystyrene copolymer as obtainedin Comparative Example 2C. Thus it was confirmed that the styrenecopolymer was a co-syndiotactic styrene copolymer.

(4) Monomer Reactivity Ratio

It is known that monomer reactivity ratios, r₁ and r₂, are importantindexes indicating a monomer chain distribution in the copolymer chain(see Coplymerization 1, Reaction Analysis, pp. 6-8, edited by KobunshiGakkai, Tokyo Japan). Polymerization was performed several times in thesame manner as in Example 1C except that the ratio of charged monomerswas changed and the degree of polymerization was controlled at a lowerlevel (not more than 5%). On basis of the compositions of the copolymersobtained, the monomer reactivity ratio was determined by the curvefitting method. It was found that r₁ (styrene)=0.420, r₂(p-methylstyrene)=1.568, and the product of r₁ and r₂ i.e., r₁.r₂, was0.659. these values showed that the styrene copolymer obtained inExample 1 was a random copolymer, and further supported the results ofthe ¹³ C-NMR spectrum.

Summarizing the results of (1), (2), (3) and (4) above, it was confirmedthat the styrene copolymer obtained in Example 1C had a substantiallyco-syndiotactic stereostructure.

                  TABLE 1C                                                        ______________________________________                                                          Aromatic Ring C.sub.1 Carbon                                       p-Methylstyrene                                                                          Signals (.sup.13 C--NMR)                                             Content      Styrene C.sub.1                                                                         p-Methylstyrene                               Run No.  (mol %)      (ppm)     C.sub.1 (ppm)                                 ______________________________________                                        Example 1C                                                                             7            145.11    142.09                                                              145.22                                                  Comparative                                                                            6            145.1-146.1                                                                             --                                            Example 1C                                                                    Comparative                                                                            7            146.26    143.15                                        Example 2C            146.37                                                  Syndiotactic                                                                           0            145.11    --                                            Polystyrene                                                                   Syndiotactic                                                                           100          --        142.40                                        Poly(p-                                                                       methyl-                                                                       styrene)                                                                      ______________________________________                                    

EXAMPLE 2C

A styrene copolymer was produced in the same manner as in Example 1 (2)except that a mixture of 250 mmol of styrene and 250 mmol ofp-methylstyrene was used as the monomer feed. The styrene copolymer thusobtained was extracted with methyl ethylene ketone.

The properties of the styrene copolymer are shown in Table 2C, andaromatic ring C₁ carbon signals of the ¹³ C-NMR spectrum of the styrenecopolymers are shown in FIG. 6A.

EXAMPLE 3C

A styrene copolymer was produced in the same manner as in Example 1C(2)except that a mixture of 50 mmol of styrene and 450 mmol ofp-methylstyrene was used as the monomer feed. The styrene copolymer thusobtained was extracted with methyl ethyl ketone.

The properties of the styrene copolymer are shown in Table 2C, andaromatic ring C₁ carbon signals of the ¹³ C-NMR spectrum of the styrenecopolymer are shown in FIG. 7A.

EXAMPLE 4C

A styrene copolymer was produced in the same manner as in Example 1C(2)except that a catalyst consisting of 0.02 mmol ofcyclopentadienyltitanium trichloride and 10 mmol (as aluminum atom) ofmethylaluminoxane was used as the catalyst and a mixture of 450 mmol ofstyrene and 50 mmol of p-methylstyrene was used as the monomer feed. Thestyrene copolymer thus obtained was extracted with methyl ethyl ketone.

The properties of the styrene copolymer are shown in Table 2C andaromatic ring C₁ carbon signals of the ¹³ C-NMR spectrum of the styrenecopolymer are shown in FIG. 8A.

EXAMPLE 5C

A styrene copolymer was produced in the same manner as in Example 1C(2)except that a mixture of 475 mmol of styrene and 25 mmol ofp-tert-butylstyrene was used as the monomer feed. The styrene copolymerwas extracted with methyl ethyl ketone.

The properties of the styrene copolymer are shown in Table 2C andaromatic ring C₁ carbon signals and C₄ carbon signals of the ¹³ C-NMRspectrum of the styrene copolymer are shown in FIG. 9A(a), and the ¹H-NMR spectrum is shown in FIG. 9A(b).

EXAMPLE 6C

A styrene copolymer was produced in the same manner as in Example 1C(2)except that a catalyst consisting of 0.05 mmol of tetraethoxytitaniumand 40 mmol (as aluminum atom) of methylaluminoxane was used as thecatalyst, a mixture of 250 mmol of styrene and 250 mmol ofp-tert-butylstyrene was used as the monomer feed, and polymerization wasperformed for 4 hours. The styrene copolymer thus obtained was extractedwith methyl ethyl ketone.

The properties of the styrene copolymer are shown in Table 2C, andaromatic ring C₁ carbon signals and C₄ carbon signals of the ¹³ C-NMRspectrum of the styrene copolymer are shown in FIG. 10A.

For comparison, C₁ carbon signals and C₄ carbon signals of thesyndiotactic poly(p-tert-butylstyrene) described in Japanese PatentApplication Laid-open No. 104818/1987 are shown in FIG. 11A(b) and the ¹H-NMR spectrum is shown in FIG. 11A(b).

EXAMPLE 7C

A styrene copolymer was produced in the same manner as in Example 1C (2)except that a mixture of 450 mmol of styrene and 50 mmol ofm-methylstyrene was used as the monomer feed. The styrene copolymer thusobtained was extracted with methyl ethyl ketone.

The properties of the styrene copolymer are shown in Table 2C, Aromaticring C₁ carbon signals of the ¹³ C-NMR spectrum of the styrene copolymerare shown in FIG. 12A(a), and the ¹ H-NMR spectrum is shown in FIG.12A(b).

EXAMPLE 8C

A styrene copolymer was produced in the same manner as in Example 7Cexcept that a mixture of 125 mmol of styrene and 125 mmol ofm-methylstyrene was used as the monomer feed. The styrene copolymer thusobtained was extracted with methyl ethyl ketone.

The properties of the styrene copolymer are shown in Table 2C, andaromatic ring C₁ carbon signals of the ¹³ NMR spectrum of the styrenecopolymer are shown in FIG. 13.

For comparison, C₁ carbon signals of the ¹³ C-NMR spectrum of thesyndiotactic poly(m-methylstyrene) described in Japanese PatentApplication Laid-open No. 104818/1987 are shown in FIG. 14A(a), and the¹ H-NMR spectrum is shown in FIG. 14A(b).

EXAMPLE 9C

A styrene copolymer was produced in the same manner as in Example 1C(2)except that a catalyst consisting of 0.025 mmol ofcyclopentadienyltitanium trichloride and 20 mmol (as aluminum atom) ofmethylaluminoxane was used as the catalyst and a mixture of 125 mmol ofstyrene and 125 mmol of p-fluorostyrene was used as the monomer feed.The styrene copolymer thus obtained was extracted with methyl ethylketone.

The properties of the styrene copolymer are shown in Table 2C andaromatic ring C₁ carbon signals of the ¹³ C-NMR spectrum of the styrenecopolymer are shown in FIG. 15A.

For comparison, C₁ carbon signals of the ¹³ C-NMR spectrum of thesyndiotactic poly(p-fluorostyrene) described in Japanese PatentApplication Laid-open No. 104818/1987 are shown in FIG. 16A.

EXAMPLE 10C

A styrene copolymer was produced in the same manner as in Example 1C(2)except that a catalyst consisting of 0.05 mmol ofcyclopentadienyltitanium trichloride and 5 mmol (as aluminum atom) ofmethylaluminoxane was used as the catalyst and a mixture of 250 mmol ofstyrene and 167 mmol of p-chlorostyrene was used as the monomer feed.The styrene copolymer thus obtained was extracted with methyl ethylketone.

The properties of the styrene copolymer are shown in Table 2 andaromatic ring C₁ carbon signals of the ¹³ C-NMR spectrum of the styrenecopolymer are shown in FIG. 17A.

EXAMPLE 11C

A styrene copolymer was produced in the same manner as in Example 1C(2)except that a catalyst consisting of 0.05 mmol ofcyclopentadienyltitanium trichloride and 40 mmol (as aluminum atom) ofmethylaluminoxane was used as the catalyst, a mixture of 150 mmol ofstyrene and 350 mmol of p-chlorostyrene was used as the monomer feed,and polymerization was performed for 4 hours. The styrene copolymer thusobtained was extracted with methyl ethyl ketone.

The properties of the styrene copolymer were shown in Table 2C, andaromatic ring C₁ carbon signals of the ¹³ C-NMR spectrum of the styrenecopolymer are shown in FIG. 18A.

For comparison, C₁ carbon signals of the ¹³ C-NMR spectrum of thesyndiotactic poly(p-chlorostyrene) described in Japanese PatentApplication Laid-open No. 104818/1987 are shown in FIG. 19A.

EXAMPLE 12C

A styrene copolymer was produced in the same manner as in Example 9Cexcept that a mixture of 125 mmol of styrene and 125 mmol ofp-bromostyrene was used as the monomer feed. The styrene copolymer thusobtained was extracted with methyl ethyl ketone.

The properties of the styrene copolymer are shown in Table 2C andaromatic ring C₁ carbon signals of the ¹³ C-NMR spectrum of the styrenecopolymer are shown in FIG. 20.

For comparison, C₁ carbon signals of the ¹³ C-NMR spectrum of thesyndiotactic poly(p-bromostyrene) described in Japanese PatentApplication Laid-open No. 104818/1987 are shown in FIG. 21A. T2 TABLE2C-Catalyst Polymerization Monomer -Methyl Conditions Comonomer - Amountaluminoxane Time Temperature Styrene Amount -Run No. Type (mmol) (mmol)(min) (°C.) (mmol) Type (mmol) -Example 1C Ti(OEt)₄ *⁴ 0.05 5 120 50 475p-methylstyrene 25 -Example 2C Ti(OEt)₄ *¹ 0.05 5 120 50 250p-methylstyrene 250 -Example 3C Ti(OEt)₄ *¹ 0.05 5 120 50 50p-methylstyrene 450 -Example 4C CpTiCl₃ *² 0.02 10` 120 50 450p-methylstyrene 50 -Example 5C Ti(OEt)₄ *¹ 0.05 5 120 50 475p-tert-butylstyrene 25 -Example 6C Ti(OEt)₄ *¹ 0.05 40 240 50 250p-tert-butylstyrene 250 -Example 7C Ti(OEt)₄ *¹ 0.05 5 240 50 450p-methylstyrene 50 -Example 8C Ti(OEt)₄ *¹ 0.05 5 240 50 125m-methylstyrene 125 -Example 9C CpTiCl₃ 2² 0.025 20 120 50 125p-fluorostyrene 125 -Example 10C CpTiCl₃ *² 0.05 5 120 50 250p-chlorostyrene 167 -Example 11C CpTiCl₃ *² 0.05 40 240 50 150p-chlorostyrene 350 -Example 12C CpTiCl₃ *² 0.025 20 120 50 125p-bromostyrene 125 -Properties of Styrene Copolymer -Extraction ResidueComonomer Content Molecular Weight Transition Temperature -Run No. Yield(g) (wt %) (mole %) Me*³ Mn*⁴ Tg*⁵ (°C.) Tm*⁶ (°C.) -Example 1C 8.2 99 7360,000 200,000 100 246 -Example 2C 11.1 57 63 230,000 99,000 104 ---Example 3C 3.0 20 80 260,000 77,000 109 172 -Example 4C 17.8 77 1479,000 45,000 98 198 -Example 5C 7.3 77 7 390,000 210,000 103 215-Example 6C 39 35 53 93,000 37,000 124 -- -Example 7C 1.7 84 21 390,00038,000 91 232 -Example 8C 1.1 71 63 320,000 120,000 80 185 -Example 9C12.3 69 6 49,000 19,000 97 253 -Example 10C 8.7 82 5 65,000 41,000 97240 -Example 11C 21.2 31 26 35,000 11,000 92 185 -Example 12C 4.9 64 758,000 38,000 99 228 -

The styrene polymers of the present invention are novel polymers. Thecopolymers have a co-syndiotactic stereostructure that has not beenobtained in the art. The styrene polymers (both homo and copolymers)have highly syndiotactic stereostructure. Thus, the styrene polymers ofthe present invention are much superior in heat resistance to commonlyused styrene polymers such as atactic polystyrene and other styrene homoand copolymers, and further are excellent in chemical resistance.Accordingly, the styrene polymers of the present invention can beutilized as materials for production of articles satisfying the aboverequirements. Moreover, when a functional substituent is introduced inthe side chain of benzene ring, the resulting styrene polymers can bewidely used as functional polymers.

Additional methods by which the syndiotactic homopolymers and copolymersof the present invention can be produced are described in GazettaChemica Italiana, 117, 249-250 (1987); Marcromolecules 1989, 22,2129-2130; U.S. Pat. No. 4,808,680 to Schmidt et al; and U.S. Pat. No.4,774,301 to Campbell, Jr. et al.

According to Campbell a catalyst is used which is the reaction productof polymethylaluminoxane and a zirconium (IV) complex corresponding tothe formula: ZrXR₃, wherein X is halide or R, and R is independentlyeach occurrence selected from the ligand group of alkoxides andaryloxides corresponding to the formula: OR', amides corresponding tothe formula: NR'₂, phosphides corresponding to the formula: PR'₂, andβ-diketonates corresponding to the formula: R'--C(O)--CH--C(O)--R', andR' is alkyl or aryl of up to 12 carbons for a process for thepreparation of polymers of vinyl aromatic monomers having a high degreeof syndiotacticity.

According to Schmidt a catalyst is used which is the reaction product ofpolymethylaluminoxane and a cyclopentadienyl zirconium (IV) complexcorresponding to the formula: CpZrR₃, wherein Cp is a π-bondedcyclopentadienyl or substituted cyclopentadienyl ligand having from 5 to20 carbons, and R is independently each occurrence selected from theligand group of halides: alkoxides and aryloxides corresponding to theformula: OR'; amides corresponding to the formula: NR'₂ ; phosphidescorresponding to the formula: PR'₂ ; and β-diketonates corresponding tothe formula: R'--C(O)--CH--C(O)--R', and R' is alkyl or aryl of up to 12carbons for a process for the preparation of polymers of vinyl aromaticmonomers having a high degree of syndiotacticity.

The Macromolecules article, by Zambelli et al, describes testing of anumber of transition metal (Ti and Zr) compounds/methylaluminoxanecatalytic mixtures for their effectiveness to cause the syndiotacticpolymerization of styrene.

The Gazetta Chemica Italiana article, by Grassi et al, reports highlyselective synthesis of syndiotactic polystyrene using soluble titaniumor zirconium compounds with methyaluminoxane.

The present invention has been described in the above reference tospecific embodiments. However, it would be obvious to persons skilled inthe art that various changes and modifications to the embodiments may bemade, which fall within the scope claimed for the invention as set outin the appended claims. The above specification should therefore beinterpreted in a descriptive and not in a limitive sense.

What is claimed is:
 1. A syndiotactic styrene polymer having a repeatingunit represented by the general formula (I): ##STR14## wherein R isselected from the group consisting of hydrogen, halogen, C₁ -C₂₀ alkyl,halogen substituted C₁ -C₂₀ alkyl and C₁ -C₁₀ alkoxy, n is an integer of1 to 3, wherein said styrene polymer has a degree of polymerization ofnot less than 5, and mainly syndiotactic stereoregularity.
 2. Thesyndiotactic styrene copolymer of claim 1, wherein the syndiotacticityin terms of the racemic pentad is not less than 50%.
 3. The syndiotacticstyrene polymer of claim 1, which is a polymer selected from the groupconsisting of polystyrene, poly(alkyl-styrene), poly(halogenatedstyrene), poly(halogen-substituted alkylstyrene), poly(alkoxystyrene).4. The syndiotactic polymer of claim 1, wherein said polymer issyndiotactic polystyrene.
 5. The syndiotactic styrene polymer of claim 1wherein said polymer is styrene-p-methylstyrene copolymer.